Microchip Switching Regulator, 5V dc Output Voltage, 5V dc Input Voltage, 550mA Output Current, 1 Outputs

The Microchip MCP1643 is a compact, high-efficiency, fixed frequency, synchronous step-up LED driver with constant current, that operates from one and two-cell alkaline and NiMH/NiCad batteries. The device can also drive two red/green/yellow series connection LEDs.

1.6A Typical Peak Input Current Limit
Up to 550 mA LED Load Current
Low Start-up Voltage: 0.65V (typical, 25 mA LED Current)
Low Operating Input Voltage: down to 0.5V
Maximum Input Voltage < VLED<5.0V
Maximum Output Voltage: 5.0V